Neutral Safety, Starter Protection

NEUTRAL SAFETY, STARTER PROTECTION, REPLACEMENT PARTS, DIAGNOSIS AND TROUBLESHOOTING

NEUTRAL SAFETY FUNCTION
The transmission range selection input of automatic transmission equipped vehicles also allows the relay to provide the neutral safety switch function. The internal relay contact will open if the signal goes low indicating the transmission range selector is in a drive gear.

STARTER PROTECTION
Starting with June 1994 production, the DME "TD" (engine speed) signal was also added to the inputs of the starter immobilization relay. This additional input allowed the relay module to provide the starter protection feature. The internal relay contact opens if the TD signal exceeds 60 Hz. 60 Hz equals the following engine speeds:

4 cylinder engine = 1800 RPM
6 or 12 cylinder engines = 1200 RPM
8 cylinder engine = 900 RPM

The relay contacts will close when the exceeded Hz value drops to 5Hz below the max. This only intended as a safety feature to prevent starter motor activation when the engine is running above these speeds.

REPLACEMENT PARTS
The Starter Immobilization Relays are different on automatic and manual transmission vehicles. If these relays are interchanged, the vehicle will demonstrate a no crank condition. Additionally, the part numbers change again for vehicles produced after 6-94 for the inclusion of the Starter Protection feature. Always verify Part Numbers using the EPC or current parts microfiche.